1. Field of the Invention
The present invention relates to a three-dimensional display device, and more particularly to a technique which is effectively applicable to a three-dimensional display device of a DFD (Depth Fused 3D) type which arranges a plurality of display panels (display screens) in the depth direction in an overlapped manner.
2. Description of Related Arts
Conventionally, as a three-dimensional display device which displays a three-dimensional image such as a three-dimensional stereoscopic image of an object or an image which arranges a plurality of objects three-dimensionally, there has been known a display device of a DFD type.
The above-mentioned display device of a DFD type is a three-dimensional display device which arranges a plurality of display panels (display screens) at different depth positions as viewed from a viewer of the display device (for example, Japanese Patent Laid-open No. 2002-214566 (patent document 1)). In the three-dimensional display device described in the above-mentioned patent document 1 or the like, two-dimensional images which are obtained by projecting an object to be displayed on the respective display screens from the viewing direction of the viewer are generated, and are displayed on the respective display screens. Then, the transmissivities of the two-dimensional images displayed on the respective display screens as viewed from the viewer are respectively independently changed for respective display screens thus generating a three-dimensional stereoscopic image.
Here, for example, in the display device having two display panels, the transmissivity of the front-side display panel as viewed from the viewer is set such that the brightness of the two-dimensional image which is displayed on the front-side display panel becomes equal to the brightness of the object to be displayed, and the transmissivity of the depth-side display panel as viewed from the viewer is set to a maximum value of the display panel, for example. Due to such a constitution, it appears to the viewer as if the object to be displayed is displayed on the front-side display panel. Further, by slightly increasing the transmissivity of the front-side display panel and by slightly decreasing the transmissivity of the depth-side display panel, it appears to the viewer as if the object to be displayed is displayed at a depth position corresponding to a rate of transmissivities of the respective display panels. In this manner, in the above-mentioned display device of a DFD type, it is possible to display an image of the object at the arbitrary depth position between the display panels by independently changing the transmissivity of the front-side display panel and the transmissivity of the depth-side independently from each other so as to change a ratio between the transmissivities thereof.
The above-mentioned three-dimensional display device of a DFD type allows the viewer to observe the three-dimensional stereoscopic image without using particular glasses for stereoscopic observation such as a liquid crystal shutter glass, for example, thus suppressing the contradiction among physiological factors in stereoscopic vision.